I. Field of the Invention
The invention relates to a cardboard tampon applicator. More particularly, the invention relates to a cardboard or paper laminate tampon applicator having a pierce-through fingergrip and an outer surface that is coated with an epoxy resin. The epoxy coated cardboard tampon applicator of the present invention can be formed inexpensively, without using volatile solvents, and will have a high degree of gloss for easier insertion, as well as improved cross-sectional circularity for reduced ejection force.
II. Description of the Prior Art
Tampon applicators are generally either a molded thermoplastic material, such as plastic, or a paper laminate, such as cardboard or paperboard.
Molded plastic can be used to form a tampon applicator. It is desired that such applicators have a generally circular cross-sectional shape. Maintaining this generally circular shape has been found to reduce the force needed to eject the tampon pledget from the applicator. Further, molded plastic applicators can be formed with a high degree of surface smoothness, which results in increased comfort during insertion of the tampon. However, plastic tampon applicators, unless certain expensive plastics are used, are neither water dispersible nor biodegradable. In an ecology minded society, biodegradability is desired.
To obtain biodegradability, a cardboard or paper laminate applicator is preferred since such applicators delaminate upon saturation with water, thereby facilitating biodegradation. However, a film laminated paper applicator is difficult to form with a perfectly circular cross-section, and the degree of circularity of the laminated paper applicator has been found to further degrade during the tube forming heating stage of the manufacturing process. Moreover, the fingergrip in such an applicator is important, but at the same time difficult to form with sufficient gripability.
Some commercially sold cardboard applicators have applied thereto either a separate film coat bonded by adhesive, or a liquid coating which then solidifies. A liquid wax coating is inexpensive to apply, and will not degrade the circularity of the tampon applicator during the manufacturing process. However, such liquid wax-coated tampon applicators do not have the desired surface smoothness and, therefore, do not provide the desired insertion comfort and reduced ejection force.
A polyester film coating, which has been used on commercially sold tampon applicators, has been found to shrink during the heating cycle of the applicator manufacturing process, causing the distortion of the applicator's shape thereby increasing the ejection force. A cellophane film also shrinks due to the evaporation of water absorbed from the adhesive used to apply it to the applicator. Further, cellophane is usually coated with a water resistant coating, such as nitrocellulose. Nitrocellulose coating of cellophane is expensive, and requires the use of a volatile organic solvent to apply the coating. The use of such a solvent requires special handling and disposal procedures, all of which further raise manufacturing costs.
Liquid coated paper laminate applicators are known in the art. For example, U.S. Pat. No. 4,412,833 to Weigner, et al. is directed to an applicator formed of a high-gloss paper that can be coated with a degradable, dispersible or water soluble polymer, such as a modified polyethylene, polypropylene, polyvinylidene chloride or polyvinyl alcohol. U.S. Pat. No. 4,508,531 to Whitehead, provides an applicator with a heat-sensitive coating, such as polyolefin (e.g., polyethylene or polypropylene) or a heat sensitive adhesive.
U.S. Pat. No. 4,622,030 to Shelton provides a thermoplastic coated paper tube. A film layer on a paper laminate tampon applicator is disclosed in U.S. Pat. No. 5,346,468 to Campion et al. This paper laminate tampon applicator has a thermoset polymer film layer adhered to the outer surface of the cardboard applicator. Preferably, this polymer film layer is a cellophane layer. However, there can be nitrocellulose over cellophane, and allegedly, in place of cellophane, a film layer of a thermoplastic polymer such as polyethylene, polyester, polypropylene, polycaprolactone or ethylene vinyl acetate.
Neither the liquid nor film coatings applied to the cardboard tampon applicators described above have permitted the combination of formation of the desired glossy finish, retention of applicator circularity, and sufficient biodegradability. Further, some prior art liquid coatings are more expensive, and require the use of organic solvents, leading to increased consumer cost.
There is a commercial tampon applicator by Paragon that has an epoxy coat. However, this applicator does not have the multiple puncture fingergrip of the present applicator and may not appreciate the significant circularity improvement provided by an epoxy coating.
The present invention is directed to applying a liquid coat on the surface of the paper laminate or cardboard applicator, and thereafter forming a multiple puncture fingergrip on the applicator. The formed applicator has the desired high gloss finish and maintains the improved degree of circularity of the applicator, while still permitting water dispersibility and biodegradability. The liquid coating of the present invention provides for the formation of the multiple puncture fingergrip, is inexpensive to apply, and does not require the use of organic solvents in the manufacturing process.